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T. F. ME-THVEN. COMPRESSED AIR summs AND REVERSING VALVE GEAR FOB comausnou ENGINES.- APPLICATION FILED SEPT. I2, 1918.

1 ,318,897. J Patented Oct. 14,1919.

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THOMAS FORRET METHVEN', OF DALMUIR, SCOTLAND.

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Specification of Letters Patent.

Patented Oct-14, 1919.

Application filed September 12, 1918. Serial No. 253,730.

To all whom it may concern: 7 7

Be it known that I, THOMAS Fonnn'r MElI-IVEN, a subject of the King of Great Britain and Ireland, and a resident of Dalmuir, Scotland, have invented certain new and useful Improvements in Compressed- Air Starting and Reversing Valve-Gears for Combustion-Engines, of which the fol- The invention has for its. object .to provide for combustion engines which are started and reversed by compressed air ime proved'andsimplified-valve gear for controlling the admission of air to the engine cylinder or cylinders for these purposes.

The improved valve gear is'of the type comprising a valve-member controlling ports communicating with the cylinder or cylinders and operatively connected thereto a piston member by which by means of compressed air the valve member may bethrown a predetermined distance in one or other direction from amid and neutral position. According to the invention there is also operatively connected to the valve 'member a tappet device which, when the valve memher is moved by the piston member, is thrown into the path of a tappet on apart i of the'engine rotating or moving at engine speed. The valve member is so devised that when the tappet member is thrown into the path of the tappet in one direction the valve member is moved against the pressure exerted on the piston member to uncover the ports. communicating between the engine cylinder or cylinders and the source of compressed air 1n such phase that the.

engine is started in onedirection, and when the'tappet member is thrown in the opposite direction the tappet so operates the valve member that the engine is started in the reverse direction. 'Means are provided for controlling the supply of compressedair to the piston member in known mannerpreferably by valves cam-operated from ahandwheel-in suchwise that the piston member may be held in neutral position (in which I the whole valve gear is inoperative) or be thrown in one or other-direction as desired.

In carrying out the invention the valve member and the piston member may very conveniently be in the form of a single piston valve arranged in a cylindrical casing provided withcompressed air inlets at its ends. The piston valve has a central dia-v phragm, acting as the piston member, and a series of'ports in its periphery coactlng with ports in the casing and so forming the valve member. The tappet member may very conveniently consist of alever pivoted on a fixed pivot, operatively connected to the piston valve and having in it a jaw which normally lies clear ofa tappet pin moved by the engine but one or other side of which jaw is thrown into the path of the pin when the piston valve is thrown in one or other direction.

A simpleillustrative example of this manner of carrying out the invention is-shown in sectional elevation and to some extent diagrammatically on anaccompanying sheet of explanatory drawings. 1

In this example, which is applicable to atwo-cylinden engine, the piston valve A with-its centraldiaphragm B is arranged in a casing C to the ends of which -'compressed air has access by way of pipes D, E;

Ports F, G, H, I'in the piston valve coact withports J, K,'L, M in the-casing to distribute compressed air to manifolds N, O and from thence by pipes I, R'to the engine cylinders. The piston valve A, shown in neutral position,'has in it a pin S passing out through a slot in the casing andengaged by-a lever T pivoted on a fixed fulcrum pin U, held in mid position by a spring (not shown) and having a jaw V adapted to be engaged by a'pin W on an eccentric strap X. which may'very' conveniently be that by which the engine fuel and water pumps are driven;

The supply of compressed air by way of the pipes D, E, to throw the. piston valve A in one or other direction, is controlled by Compressed air is supplied to the space above these valves by a Y pipe E and'the pipes D, E are connected to the space beneath the valves. 7

Either of these valves A B can be raised from its seat by a cam F on a spindle G which spindle is provided with a push button II and is movable endwise against the pressure of a spring J being retained when it is pushed upward by a spring con trolled detent L which engages a groove M in it. A handwheel N is carried on a' feather Q on the spindle, and this spindle and handwheel may very conveniently be those by which the supply of fuel to the engine is controlled by further mechanism not shown.

In operation, to start the engine in the one direction, the handwheel is rotated so that the cam raises say the valve A from its seat. Compressed air then passes by Way of the pipe D to the left hand end of the casing C throwing the piston valve A to the right and bringing the left-hand side of the jaw V into the path of the pin IV. Air has then access to the engine cylinders by Way of the ports F, G, J, L and the engine starts. The pin IV then encountering the jaw V so operates the piston valve A against the air pressure acting on it, to keep the engine running in the direction in Which it is started. When the engine is running the spindle G is raised and the cam F then passes out of engagement with the valve A which immediately closes, cutting off the supply of air to the piston valve A which thereupon is returned to mid position by the action of its spring on the aw V and the starting device becomes inoperative. At the same time the cam F is held in its raised position by engagement of the detent L with the groove M and the handwheel N and spindle G may now be operated in'usu'al manner to control the fuel supply and so the speed of the engine.

If the handwheel be now turned back the cam is released by reason of the detent L passing out of the groove il by way of an inclined slot R and upon the handwheel being turned farther in the opposite direction raises the valve B and causes the piston valve A to be thrown in the opposite direction, so starting the engine in the opposite direction also.

What I claim is 1. In a compressed air starting valve-gear device of the type described, a valve cas ing with lateral ports, a nonrotary piston valve working therein with ports in the valve skirt adapted to register with the lateral ports in the valve casing, means communicating with the lateral ports in the valve casing to lead the air therefrom to the engine cylinders, and means for leading to one side of the valve diaphragm a supply of compressed air to shift the valve in its casing, in combination with engine operated means for reciprocating the valve in the shifted position to control the distribution of air thereby to the engine cylinders.

2. In a construction such as specified in claim 1, engine-operated means comprising a lever pivoted at a fixed point and operatively connected to the valve, an engine moved tappet and a jaw on the lever engaging said tappet with lost motion.

8. In a construction such as specified in claim 1, means for controlling the supply of compressed air to the piston valve comprising a tappet valve normally closing the air conduit leading to the valve, a cam for operating said tappet valve, a rotatable and endwise-movable spindle on which said cam is mounted and by which said cam is moved into operative position on rotation, or into inoperative position by endWise movement, and means for holding said shaft when moved endwise for the purposes set forth. r a. In a compressed air starting and reversing valve-gear device of the type de scribed, a valve casing with groups of lateral ports, a non-rotating piston valve working therein and having a central diaphragm with ports in the vvalve shirt on opposite sides of said diaphragm adapted to register with the respective lateral port groups in the casing, means communicating with the port groups in the valve casing to lead the air therefrom to the engine cylinders, and means for leading to opposite sides of the valve diaphragm a supply of compressed air to shift the valve in one direction or the other in its casing, in combination with engine operated means for. reciprocating the valve in its shifted position to control the distribution of air thereby to the engine cylinders through one or the other port group in the valve casing depending upon the direction in which the valve is shifted.

5. In a construction such as specified in claim 4, means for controlling the supply of compressed air to the piston valve, comprising a pair of conduits leading to opposite sides of the piston valve, a pair of tappet valves controlling the same, a cam for operating one or the other of said valves alternatively, a rotatable and endwise movable spindle on which said cam is mounted and by which it is moved into operative position on rotation or into inoperative position by endwise displacement, and means for holding said shaft when moved endwise, for the purposes set forth.

In testimony whereof I have signed my name to this specification.

THOMAS FORRET METHVEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

